On the development of loose cartilaginous bodies / by J.A. Kingdon.

Kingdon, J.A.

Date:: [1851]

Credit: On the development of loose cartilaginous bodies / by J.A. Kingdon. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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pregnated germ-cell is remembered, whose exhaustless influence, as evi- denced in the aphides, so far exceeds the reach of finite comprehension. Cartilage is the tissue with which we are more especially concerned in this paper, and to that alone will our atten- tion be directed, without waiting to dis- cuss the peculiarities of other nucleated cell structures. This tissue is com- paratively simple in its structure, being made up entirely of nucleated cells im- bedded iu a structureless intercellular, or hyaline substance. The cells them- selves closely resemble those of the vegetable; their outer cell-walls are clearly defined and homogeneous, their nuclei distinct, and their arrangement such as would indicate fissiparity, for they are found ofteu marked with slight hour glassindentations, with half-formed diaphragms, and still more frequently are two or more of them found lying in juxtaposition with a narrow cleft be- tween them. This notion of fissiparous reproduction is still further supported by the miuute investigation of the dis- ease known as “ ulceration of cartilage,” where the cells, and more especially the nuclei, divide and subdivide so rapidly as to break up the cartilage into a finely molecular condition, similar in appear- ance to fatty degeneration of other organs : from which we may reasonably infer that this power of reproduction is quite independent of growth, and seems to be inherited by the nucleus from the primitive germ-cell, which after impreg- nation so rapidly multiplies its contents without a corresponding increase of its own dimensions. Besides this power of reproduction, the cartilage cell, in common with those of all animals, possesses a power of attracting into its substance material for its development and growth, by which means the struc- ture in which it is situated is maintained; so that it may be said to have the “ double life” spoken of by Schleiden as being a characteristic of vegetable cells. How does cartilage grow ? According to our argument it should be through the agency of the nuclei attracting nourishment into the hyaline substance, and from thence imbibing it for its own increase: and doubtless this is the case. But in what order are thecells developed, and whence is the material for their increase obtained ? To the first part of this question no definite answer can be given, since all cartilages have not an identical mode of growth. In ossifying cartilage, as a matter of abstract reasoning, it must be evident that as the process consumes fully developed cells, the new material essential for its continuance must be deposited beyond the seat of its action. Now it has been a matter of much dis- pute whether these new cells are de- veloped at the margin or in the sub- stance of this ossifying cartilage: a little investigation will show that both are synchronous, for in a section of the ex tremity of one of the long bones during its early and rapid growth can be seen the gradations from the simple, singly- nucleated, miuute cells, which are to be found most remote from the part where ossification is proceeding, to the com- pound group of doubly nucleated and nucleolated cells formed by fissiparation, and still held together, as it were, in bundles by a faint trace of the original cell-wall. This maybe observed in almost any part of the advanced foetal skeleton; and in a transverse section of the costal cartilage prior to the development of blood-vessels witliin it, the marginal cells will be found to be smaller, and to contain fewer nuclei than those situated towards the centre: hence, if it be allowed that the smaller cells are the younger, to which admission it is hard to find a valid objection, we must, to a certain extent, allow cartilage to have an exogenous mode of formation; for the fact quoted in evidence of an endo- genous formation,—namely, the hori- zontally flattened condition of the more superficial cells, supposed to be produced by pressure from within, in no way militates against the former view, but rather gives it support, by showing that the cells do not arrive at maturity soon after their production, but still go on increasing and multiplying, and thus press against and tend to flatten those more recently developed outside them. There is also good reason to believe that the permanent articular cartilage is formed in a similar manner; but whe- ther, after having arrived at maturity, its farther nutrition is carried on by the formation of new cells, or by the mere renewal of the constitutional atoms of those already existing, is a question still to be decided, although the latter view is certainly the most reasonable. Whence is it nourished? In vascular cartilages the source is evident; but in those that receive no bloodvessels, as

On the development of loose cartilaginous bodies / by J.A. Kingdon.

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